养殖牡蛎有助于振兴切萨皮克湾

The Chesapeake Bay could get helped by a new antipollution expert: farmed oysters. For decades, the Chesapeake has been plagued by excess nutrients, such as nitrogen, from agricultural and municipal run-off. The nutrients feed algal blooms, which suck up the oxygen in the water. And those oxygen-poor waters no longer support the Bay’s rich biodiversity.

The Chesapeake used to be home to wild oysters, but 99 percent of them are gone. The tasty bivalves are known for removing excess phytoplankton from water and sequestering nutrients in their shells and flesh. So scientists from Virginia Commonwealth University measured the nutrient-chomping potential of the Eastern oyster Crassostrea virginica.

They tested dried tissue and shells from oysters in two aqua-culture sites. Turns out that if a farmed oyster grows to 76 millimeters, it’s a pretty effective water filter. Eight large-scale oyster farms could clean a ton of nitrogen from the Chesapeake. The study was published in the Journal of Environmental Quality. [Colleen Higgins, Kurt Stephenson and Bonnie Brown, Nutrient Bioassimilation Capacity of Aquacultured Oysters: Quantification of an Ecosystem Service]

Such farming won’t make the bay pristine again, but the researchers say the oysters are effective at cleaning the area where they’re grown. And so for a biologically better Chesapeake, pass the hot sauce.

—Cynthia Graber